21368960 has 64 divisors (see below), whose sum is σ = 51646680. Its totient is φ = 8454144.

The previous prime is 21368953. The next prime is 21368987. The reversal of 21368960 is 6986312.

It can be written as a sum of positive squares in 4 ways, for example, as 18731584 + 2637376 = 4328^2 + 1624^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 21368960.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110624 + ... + 110816.

Almost surely, 2^21368960 is an apocalyptic number.

21368960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21368960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25823340).

21368960 is an abundant number, since it is smaller than the sum of its proper divisors (30277720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21368960 is a wasteful number, since it uses less digits than its factorization.

21368960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385 (or 373 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 21368960 is about 4622.6572444861. The cubic root of 21368960 is about 277.4988123208.

The spelling of 21368960 in words is "twenty-one million, three hundred sixty-eight thousand, nine hundred sixty".